using Microsoft.EntityFrameworkCore;
using SchoolAgainStudyContracts.BindingModel;
using SchoolAgainStudyContracts.SearchModel;
using SchoolAgainStudyContracts.StorageContracts;
using SchoolAgainStudyContracts.ViewModel;
using SchoolAgainStudyDataBaseImplements.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SchoolAgainStudyDataBaseImplements.Implements
{
    public class TeacherStorage : ITeacherStorage
    {
        public TeacherViewModel? Delete(TeacherBindingModel model)
        {
            using var context = new SchoolDataBase();
            var element = context.Teachers
                .FirstOrDefault(rec => rec.Id == model.Id);
            if (element != null)
            {
                context.Teachers.Remove(element);
                context.SaveChanges();
                return element.GetViewModel;
            }
            return null;
        }

        public TeacherViewModel? GetElement(TeacherSearchModel model)
        {
            if (string.IsNullOrEmpty(model.Login) && !model.Id.HasValue)
            {
                return null;
            }
            using var context = new SchoolDataBase();
            return context.Teachers
                .FirstOrDefault(x => (!string.IsNullOrEmpty(model.Login) && x.Login == model.Login) ||
                                (model.Id.HasValue && x.Id == model.Id))
                ?.GetViewModel;
        }

        public List<TeacherViewModel> GetFilteredList(TeacherSearchModel model)
        {
            if (string.IsNullOrEmpty(model.Name))
            {
                return new();
            }
            using var context = new SchoolDataBase();
            return context.Teachers
                    .Where(x => x.Name.Contains(model.Name))
                    .ToList()
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public List<TeacherViewModel> GetFullList()
        {
            using var context = new SchoolDataBase();
            return context.Teachers
                    .ToList()
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public TeacherViewModel? Insert(TeacherBindingModel model)
        {
            using var context = new SchoolDataBase();
            var newTeacher = Teacher.Create(context, model);
            if (newTeacher == null)
            {
                return null;
            }
            context.Teachers.Add(newTeacher);
            context.SaveChanges();
            return newTeacher.GetViewModel;
        }

        public TeacherViewModel? Update(TeacherBindingModel model)
        {
            using var context = new SchoolDataBase();
            using var transaction = context.Database.BeginTransaction();
            try
            {
                var teacher = context.Teachers.FirstOrDefault(rec => rec.Id == model.Id);
                if (teacher == null)
                {
                    return null;
                }
                teacher.Update(model);
                context.SaveChanges();
                transaction.Commit();
                return teacher.GetViewModel;
            }
            catch
            {
                transaction.Rollback();
                throw;
            }
        }
    }
}